X80 pipeline steel was firstly aluminised at a relative low temperature then treated by a microarc oxidation process. Electrochemical behaviour of X80 pipeline steel before and after the combined treatment was evaluated by electrochemical tests in different solution. Results show that ceramics coating composed of a-Al 2 O 3 and c-Al 2 O 3 can be obtained on the surface of X80 pipeline steel by the combined treatment. In neutral 3?5% NaCl solution and alkaline solution (pH59), X80 pipeline steel with ceramics coating shows a higher corrosion potential and a lower corrosion current density than pure steel and the X80 pipeline steel treated by one-step aluminising. However, aluminising coating presents a better corrosion protection for X80 pipeline steel than that of ceramic coating in acidic solution with pH55. c-Al 2 O 3 is considered as the main reason for the corrosion resistance degradation of ceramic coating in acidic solution.